1. Field of the Invention
The invention relates to voltage generation and, more particularly, to voltage generation internal to memory systems.
2. Description of the Related Art
Memory cards are commonly used to store digital data for use with various products (e.g., electronics products). Examples of memory cards are flash cards that use Flash type or EEPROM type memory cells to store the data. Flash cards have a relatively small form factor and have been used to store digital data for products such as cameras, hand-held computers, set-top boxes, hand-held or other small audio players/recorders (e.g., MP3 devices), and medical monitors. A major supplier of flash cards is SanDisk Corporation of Sunnyvale, Calif.
FIG. 1 is a schematic diagram of a conventional voltage generation circuit 100. The conventional voltage generation circuit 100 can provide one or more generated voltages to a memory system that provides non-volatile data storage and represents, for example, a memory card (e.g., flash card). The voltage generation circuit 100 includes a charge pump circuit 102. The charge pump circuit 102 operates to boost a lower input voltage (VIN) to produce a higher output voltage (VOUT). The output voltage is coupled to a decoupling capacitor (CD) 104. The output voltage is also coupled to a resistor divider 106. The resistor divider 106 divides the output voltage using resistors R1 and R2. A comparator 108 couples to the resistor divider 106 and to a reference voltage (VREF). The output of the comparator 108 is fed back to the charge pump circuit 102 so that the charge pump circuit 102 can regulate the output voltage so that it remains at a substantially constant voltage level.
In a unified voltage generation arrangement, a charge pump generates a high output voltage that is converted into different operational voltage levels for use by a memory system. Unfortunately, however, circuitry utilized to convert the high output voltage from a charge pump into the different operational voltage levels consumes a substantial amount of power. The power consumed by such circuitry is particularly problematic when being used with power conscious electronic devices, such as battery-powered electronic devices. Accordingly, there is a need for improved unified voltage generation circuits that can operate with improved power efficiency.